Order movies by vote average

[SantosGuillamot]

Based on feedback received, I created this pull request to order the movies by vote average instead of popularity. These are the changes made:

• Change the query loop to order by _wpmovies_vote_average meta value.
• Filter movies with less than 3000 votes.
• Use getTopRated instead of getPopular to get the top rated movies.
• Change break for continue in the adult filter to keep importing the rest of the movies.
• Update the XML files.